System And Method For Producing A Consistent Quality Syngas From Diverse Waste Materials With Heat Recovery Based Power Generation, And Renewable Hydrogen Co-Production

ABSTRACT

A system and method for converting waste and secondary materials into synthesis gas (syngas) through the use of a molten metal bath gasifier for the initial breakdown of waste feeds and an A/C plasma reactor for complete dissociation of waste feeds into syngas, and an anaerobic digester. The system includes a heat recovery and steam power generation process for the production of electricity. The system produces a net output of electricity above plant load sufficient for the co-production of renewable Hydrogen and Oxygen. The process does not require the use of fossil fuels or fossil feedstocks during normal operations, and it eliminates combustion produced stack emissions or landfill residuals.

RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication Ser. No. 61/794,471 filed on Mar. 15, 2013.

BACKGROUND

The beneficial reuse of waste materials has long been a priority in theprotection of human health and the environment. More recently, attemptshave been made to use a larger variety of waste as a manufacturingfeedstock, primarily through the use of various gasification techniques.

In the United States, the use of gasification technologies for wastedisposal has been attempted with varying degrees of success since the1970s. One of the biggest barriers to the use of waste materials as amanufacturing feedstock is the diversity of the chemical composition,moisture content, and physical characteristics of waste materials. Thisdiversity is compounded by the variations in waste material fromlocation to location, as well as changes in the characteristics of wasteover time. Unlike fossil-based feedstocks (e.g., natural gas, coal) thathave fairly consistent chemical composition and physical characteristicsfrom one location to the next, waste materials are inherently diversemaking the quality of waste-derived products more difficult to achieve.

The most common methods used to overcome the problems of waste diversityinvolve sorting; separating; mixing; or a combination of the three.Sorting and separating provides value in identifying wastes that havehigh energy value and desirable chemical compositions, but they are bothcapital and energy intensive, rendering the systems cost prohibitive.Mixing waste provides a less expensive method for homogenizing the wastefrom one batch to another, but the potential for undesirable chemicalreactions increases risks to human health and the environment.

Synthesis gas (syngas) derived products, with integrated electric powerco-generation using virgin fossil feedstocks and/or waste feedstocks,have been manufactured on an industrial scale since the mid-20^(th)Century. It is a well understood practice that essentially involves therecycling of Carbon, Hydrogen and Oxygen at the molecular level andmanaging energy efficiencies in order to optimize the financial resultsfor the systems' owners. Historically, this has meant that a portion ofthe syngas is combusted in an integrated gasification combined cycle(IGCC) system to increase net power production, at the expense of stackemissions. Given the current realities of the national energy securitysituation, there is an ever increasing demand for syngas-derivedproducts made from domestic and renewable resources. However, there isopposing pressure from environmental protection priorities to reducecombustion stack emissions and greenhouse gas emissions.

The problem with conventional approaches is the persistence of anopen-loop in the mass and energy balancing of the whole system.Zero-emissions can be achieved using conventional systems, but normallyrequire an energy input in the form of pure Oxygen, natural gas(methane) or grid power. Even though this can theoretically be solvedusing 100% renewable energy, the financial sustainability of the systembecomes questionable due to the cost of utilities.

SUMMARY OF THE INVENTION

An embodiment of the present invention overcomes the heterogeneity ofwaste issues by focusing on wastes of known composition (e.g.,weight/volume; chemical composition) that are used as feedstocks. Thisis accomplished by focusing on Industrial Solid Waste which ismanifested to comply with EPA and U.S. Department of Transportation(DOT) regulations, focusing on specific waste streams (e.g., waste frompaint manufacturers), as well as other known waste products (secondarymaterials). This specific knowledge of the waste materials that are usedas feedstocks allows the waste to be processed more effectively andsafely.

According to an aspect of the invention, the inventive process comprisesthe following steps: (a) tagging (e.g., barcode, quick response code,radio frequency identification tag [RFID]) of feedstock materials at thesource concurrent with manifesting for transportation; (b) electronicsharing of manifest information by all parties involved with generating,transporting, and beneficial reuse; (c) leveraging tagged/manifest datato maximize processing efficiency, as well as environmental health andsafety, while minimizing the risks inherent in chemical and physicalvariation in ‘unknown’ feedstocks; (d) loading of pumpablenon-biodegradable feedstocks into a filtration system to remove unwantedparticulates; (e) loading of non-pumpable non-biodegradable feedstocksinto mechanical processing equipment for size reduction withoutdecanting or other removal from shipping containers; (f) loading ofbiodegradable feedstocks into separate mechanical processing systems;and (g) slurification.

According to another aspect of the invention, the process does not relyon any fossil fuels or fossil feedstocks to be consumed during normaloperations, nor does it produce any environmentally harmful emissions orwaste byproducts requiring landfill disposal or further treatment.

In one embodiment, the invention also manages the flow and mix ofchemistry input into the system, without the physical pre-mixing ofwaste materials, through the processing of data and information aboutthe materials in an over-arching operations control and monitoringsystem.

In addition, the invention employs a multi-stage process where biogas,from an anaerobic digester, preferably has an average methane (CH₄)content of about 75%. In gasification systems, biogas is typically usedas a combustion fuel or as a commodity product. In this invention,biogas is counter-intuitively used as a waste feedstock to add energy tothe system, as well as a working gas for the plasma generator.

In another embodiment, the invention captures the heat generated fromthe various processes to create steam which is used to generateelectricity in amounts over and above processing requirements. Capturinga portion of the heat generated by the various processes employed in theinvention eliminates the need for a combustion process to generateelectricity with the associated smokestack and/or utility inputs duringnormal operating conditions.

According to yet another aspect of the invention, the process uses amolten metal bath gasifier (MMBG) to convert the non-biodegradablefeedstocks into a raw process gas comprised mostly of Hydrogen (H₂) andcarbon monoxide (CO), and an anaerobic digester to convert biodegradablefeedstocks into a raw biogas comprised mostly of methane (CH₄) andcarbon dioxide (CO₂).

While there are different MMBGs that can be used in the invention, apreferred embodiment is a MMBG with an iron bath operating between1,150° C.-1,600° C. (the melting point range for various types of Iron).While molten iron is used in the preferred embodiment, it iscontemplated that other metals may be used in the MMBG. Similarly,different types of anaerobic digesters can be used in the invention, butin a preferred embodiment a thermophilic anaerobic digester operating ina temperature range of 49° C.-57° C. is used. Using a thermophilicprocess with its higher temperature range (compared to a mesophilicprocess) provides the advantage of a higher energy yield and itfacilitates greater sterilization of the digestate.

The raw process gas from the MMBG is conveyed to a thermal dissociationreactor wherein it is ionized by exposure to a plume from an alternatingcurrent (A/C) plasma generator hot enough to complete the moleculardissociation of the raw input gases. This produces a syngas comprisedmostly of Hydrogen (H₂) and carbon monoxide (CO). The syngas is thencooled, cleaned (e.g., filtered) and conditioned as required forsynthesis into methanol and/or other primary liquid product, orseparated into its constituent industrial gas products.

The inventive process converts waste and secondary materials into syngasthrough the use of a MMBG and an A/C plasma reactor, integrated with ananaerobic digester. Solid phase materials are mechanically processed forsize reduction to facilitate passage through equipment input ports. Withlimited exceptions, non-biodegradable materials are processed using theMMBG. Biomass and other biodegradable wastes are input into anaerobicdigesters for the production of raw biogas. While liquid wastes andother pumpable materials are normally input into the MMBG forprocessing, they may be input directly into the A/C plasma reactor forstreamlined processing, particularly when the MMBG is operating atcapacity. In a preferred embodiment, the MMBG comprises an enclosed,refractory lined and jacketed vessel with multiple injection ports forfeedstocks and the other normal process inputs required for managing themolten media and the internal environment of the vessel. The vessel alsohas normal metal and slag tapping systems. The MMBG smelts most metalsand incorporates them into the molten bath. Feedstocks are injected intothe melt and are instantly dissociated upon contact with the moltenbath. The MMBG also melts silicates and others minerals which areimpounded within a molten slag layer that floats on top of the moltenmetal. In this stage of the process, the metals and minerals areperiodically recovered and processed into commodity products (e.g., pigiron and silicate slag). Everything else is converted into a dirty, rawprocess gas which is input into the A/C plasma reactor for furtherprocessing.

The use of a separate MMBG upstream from the A/C plasma reactor iscounter-intuitive since it adds additional cost to the system. Further,molten baths and plasma generators are commonly used within the samevessel to gasify materials. The advantages of separating the melt fromthe plasma reactor include the ability to use the energy from the wastefeedstocks to sustain the melt, reducing/eliminating the requirement tosustain the melt from external energy sources.

In a preferred embodiment, induction heating is used to establish themelt, after which it is maintained by the energy input from the wastefeedstock. Using the melt as a process media in this manner, rather thanjust a heat sink as in other systems, offers several advantages:

-   -   (i) an efficient method for initial dissociation of materials        due to its high operating temperatures compared to typical fixed        bed, moving bed, fluidized bed or entrained flow gasifiers;    -   (ii) faster destruction and destruction rate efficiencies (DREs)        compared to all lower temperature methods;    -   (iii) faster destruction and DRE compared to gasifiers wherein        molecular dissociation occurs primarily in the atmosphere        between the melt and the reactor ceiling, including traditional        Direct Current (D/C) plasma-arc systems. Even though the        temperature of the plasma arc itself can well exceed 7,900° C.,        the energy density of the atmosphere in the reactor vessel will        be less than that of the molten media;    -   (iv) little or no charring of carbonaceous feedstocks, an        undesirable reaction that among other things increases the        energy needed for gasification, will occur when feedstocks are        injected into the molten media. This enables an energy        efficiency gain compared to processes wherein gasification        occurs primarily in the atmosphere of the reactor vessel;    -   (v) the ability to scale the size of the MMBG and the plasma        reactor independent of each other; and    -   (vi) perhaps mostly importantly, use of the melt as working        media rather than as a heat sink significantly improves the        process and energy efficiency of downstream gas clean-up        processes by impounding a significant amount of the contaminates        inherent in the feedstocks within the molten media, and        preventing their release and incorporation into the process gas        stream.

In traditional gasification processes, the process gas would be conveyeddirectly to a series of heat recovery and syngas cleanup andconditioning systems. The present invention conveys the dirty processgas into an A/C plasma reactor to complete the molecular dissociationprocess.

The temperature of the plasma plume inside the A/C plasma reactor vesselcan exceed 7,900° C. In this invention, all material input into the A/Cplasma reactor is converted into a gaseous or plasma phase and thenbegin to condense into an extremely hot syngas. The output syngas issubsequently cooled and conditioned to remove contaminates leaving aclean mixture of Hydrogen (H₂) and carbon monoxide (CO). Although eitherA/C or D/C plasma generators may be used, (both of which can generateplasmas with energy levels greater than 7,900° C.—the threshold at whichno known molecule can survive), the A/C plasma generator is preferreddue to its significant advantages over D/C plasma technologies;primarily in that it generates a wide plume of plasma that is bettersuited for dissociating a large volume of process gas compared to therelatively very narrow arc generated by a D/C plasma generator.

In addition, A/C plasma generators typically have a lower operating costas they do not incur the cost of continuously consumed carbon electrodesas do D/C plasma generators. Moreover, the biogas from the anaerobicdigestion process may also be used as the working gas for the A/C plasmagenerator as a non-utility source of additional energy for the system.

Exposure of the process gas from the MMBG to the high energy plasmaplume created by ionizing the methane (CH₄)-rich biogas from theanaerobic digester induces complete molecular dissociation of allinputs, as well as a desirably higher ratio of Hydrogen (H₂) to carbonmonoxide (CO) in the resulting syngas.

The anaerobic digester processes biomass and other biodegradablematerials (predominately plant, animal, and food processing wastes) toproduce a raw, methane-rich biogas. This biogas is used as analternative to natural gas to increase the level of H₂ and to addadditional energy to the system. It is injected into the MMBG, and/orinto the A/C plasma reactor. It is also used as the working gas for theplasma generator. Agricultural grade solids (digestate) are recoveredfrom the digesters on a periodic basis as a commodity product.Wastewater (effluent) is either recycled to add fluids (as needed) tothe anaerobic digester or filtered and input into the MMBG forprocessing.

Multiple continuous feed anaerobic digestion process trains may be usedto maximize uptime availability of the inventive system. The digestionprocess utilizes the bacterial hydrolysis, acidogenesis, andmethanogenesis processes to convert biodegradable feedstocks into abiogas with an average methane (CH₄) content of 75%. The biogas isfiltered to remove particulates before being input into the MMBG or theA/C plasma reactor.

One major byproduct of the digestion process is wastewater (effluent).When needed, the effluent is recycled into the anaerobic digestionprocess, reducing the demand for fresh water; and/or the effluent isfiltered and beneficially re-used as a feedstock in the MMBG.Advantageously, the wastewater (H₂O), when used as a process feedstock,increases the ratio of H₂ to CO.

The other major byproduct of the digestion process is a nutrient richbio-solid commonly known as digestate. The recovered digestate hassignificant commercial value as a fertilizer and/or a soil amendmentproduct.

In one embodiment, the hot process gas from the A/C plasma reactor israpidly cooled to prevent the reformation of tars, dioxins, furans, andother undesirable compounds. In the first quench, heat is stripped tolower the temperature to approximately 800° C. The gas is then veryrapidly cooled through the 400° C. to 200° C. temperature window toprevent de novo formation of dioxins and furans. The final stagerequires the syngas to be cooled below 38° C., the optimal temperaturefor the downstream cleanup systems.

Removal of contaminates from the syngas is achieved through a series ofgas cleanup and conditioning systems including, but not limited to, hightemperature cyclones, scrubbers, granulated activated charcoal (GAC) andother filters, and other membrane technologies, as well as selective andnon-selective catalytic converters.

Syngas clean-up is also performed in a closed-loop manner, with“contaminates” (e.g., particulates, volatized metals, minerals and anyacid gases that reform) extracted as commercially valuable “recoveredresources”. For example:

(i) Chlorine is removed as either hydrochloric acid (HCl), an importantindustrial product, or as sodium chloride (NaCl), commonly known as“salt” via reaction with sodium hydroxide (NaOH),

(ii) Elemental Mercury, Lead and other metals that may have volatizedand blown through with the process gas are extracted in industrial gradeforms; and

(iii) Sulfur that was not impounded within the melt or slag is alsoextracted in a commercially valuable elemental or compound form.

The clean syngas can then be conditioned to meet the input requirementsof any number of catalytic conversion processes to produce a value-addedproduct such as methanol; Fischer-Tropsch (F-T) Synfuel; etc.

Various stages of this process produce large quantities of heat fromexothermic processes or reactions. In particular, heat generated fromthe MMBG, the plasma reactor, the anaerobic digester, the syngas coolingsystem, and the product recovery processes (when appropriate) isrecovered through a combination of thermal wraps, radiators, jacketingand other heat exchangers. The recovered heat is used to producepressurized steam to power a steam turbine plant for the production ofelectricity. The system is designed to enable the production ofelectricity over and above plant load to eliminate the dependence ongrid power during normal operating conditions. The excess electricity isused to dissociate water into commodity H₂ and O₂ gas products via anelectrolysis process.

Furthermore, given the energy inputs from multiple sources (includingthe energy contained in the molecular bonds of the feedstocks; thebiogas from the anaerobic digester; and the integral exothermicprocesses), there are numerous mass-energy balance scenarios whereinsufficient heat energy can be recaptured to generate enough electricityvia steam turbine to meet and/or exceed the energy load of the plantduring normal operating conditions. This eliminates the need to combustany portion of the syngas as a fuel in an IGCC turbine, and theopen-loop stack emissions inherent with any combustion process.

According to another aspect of the invention, the entire inventiveprocess is monitored and controlled through an integrated computerizedsystem. Commercially available sensory, monitoring and control systemsare used to manage the components of the system and the flow of matterthrough the system. While these systems function as stand-alone monitorand control systems for the discrete elements to which they areattached, all of these systems are integrated into one overarchingmonitor and control system allowing end-to-end management of the entireprocess.

Under normal operations the process does not require the use of fossilfuels or fossil feedstocks. In addition, the process does not rely onany combustion processes that would result in greenhouse gases beingreleased into the atmosphere. Under normal operating conditions theprocess emits Oxygen (O₂), Nitrogen (N₂) and trace amounts of otherelements (e.g., Argon), all of which are naturally occurring,non-harmful atmospheric elements. During some maintenance procedureswastewater is generated which is suitable for processing in any publiclyowned treatment works (POTW) or it can be reprocessed in the MMBG.

The products recovered from the inventive process are highly beneficialto numerous industrial processes. For example, syngas is commonly usedas the feedstock in a number of catalysis processes to produce a widerange of industrial, commercial and consumer products. Methanolsynthesis is one of the simplest, most well understood and easilyimplemented processes from a technical standpoint, and one of the mostenvironmentally and economically sustainable. In 2011, the U.S. methanoldemand was approximately 5.7 million metric tons, or about 1.9 billiongallons per year. The majority of methanol is made via steam reformingof natural gas (with syngas as the intermediary). About 60% of allmethanol is used in the production of formaldehyde and acetic acid, bothprecursors to numerous adhesives, glues, plastics and other materials.Other major uses include solvents, antifreeze, and windshield washerfluid. Methanol can also be converted into hexane—the primaryconstituent of motor gasoline. It is also a critical feedstock in theproduction of BioDiesel.

The process of the invention will support the syngas input requirementsof all commercial methanol synthesizers (and ancillary systems) toproduce methanol that conforms to International Methanol Producers &Consumers Association (IMPCA) specifications. Methanol synthesis is anexothermic reaction and heat recovered can also be used to augment steamgeneration for the production of electricity.

The inventive process also supports the syngas input requirements ofother product recovery platforms including F-T synthesizers used tomanufacture synthetic fuels. Non-productizable fractions of F-T processoutputs can be reused as process feedstocks preserving the closed-loopconfiguration.

According to the present invention, the system and process forefficiently converting heterogeneous waste materials (biodegradable,non-biodegradable, and secondary wastes) into a high quality syngascomprises the following aspects:

(a) a first subsystem for inputting and filtering pumpablenon-biodegradable waste;

(b) a second subsystem for inputting and resizing non-pumpable,non-biodegradable waste;

(c) a third subsystem for inputting, resizing, and slurification (asnecessary) for biodegradable waste;

(d) a molten metal bath gasifier (MMBG), preferably using an iron bath,operating between 1,150° C.-1,600° C.;

(e) an anaerobic digester, upstream from the MMBG, (preferably athermophilic anaerobic digester, operating in a temperature range of 49°C.-57° C.);

(f) an A/C plasma reactor (preferably with the plasma plume aimedupward);

(g) waste materials in (a) and (b) excludes: Universal Wastes (40 CFR273); explosives and munitions; concentrated halogens; and heavy metals;

(h) the MMBG is placed upstream from the A/C plasma reactor;

(i) the biogas generated from the anaerobic digester is used as both awaste feedstock (input to either the MMBG, the A/C reactor, or both; aswell as a working gas for the A/C plasma generator, where, in thepreferred embodiment, the biogas has an average composition 75% CH₄; 18%CO₂; 1% N₂; 5% H₂O, and 1% O₂ and other trace elements (H₂S and NH₃);

(j) filtered pumpable liquids may be input directly into the A/C plasmareactor, for increased processing capacity;

(k) waste products from various filtration processes (102; 142; 146;160) can be input back into the system (130) as a feedstock;

(l) where the entire system is closed-loop, with the exception of theventing of Oxygen (O₂), Nitrogen (N₂) and trace amounts of otherelements (e.g., Argon), all of which are naturally occurring,non-harmful atmospheric elements;

(m) the heat generated by five primary subsystems (130; 140; 150; 160;170) is recovered with heat exchangers, pumped to a Heat Recovery SteamGeneration Utility, which creates steam to drive a steam turbine, whichin turn generates electricity;

(n) the production of electricity is produced in quantities over andabove plant load requirements;

(o) the excess electricity is used to dissociate water into commodity H₂and O₂ gas products via an electrolysis process;

(p) the hot process gas from the A/C plasma reactor is rapidly cooled toprevent the reformation of tars, dioxins, furans, and other undesirablecompounds. In the first quench, heat is stripped to lower thetemperature to approximately 800° C. The gas is then very rapidly cooledthrough the 400° C. to 200° C. temperature window to prevent de novoformation of dioxins and furans. The final stage requires the syngas tobe cooled below 38° C., the optimal temperature for the downstreamcleanup systems;

(q) the syngas contaminates are removed in a closed-loop manner througha series of gas cleanup and conditioning systems including, but notlimited to, high temperature cyclones, scrubbers, granulated activatedcharcoal (GAC) and other filters, and other membrane technologies, aswell as selective and non-selective catalytic converters; commerciallyvaluable volatized metals and minerals are recovered, and non-commercialby-products are used as a waste feedstock for the MMBG;

(r) syngas clean-up is also performed in a closed-loop manner, with‘contaminates’ (e.g., particulates, volatized metals, minerals and anyacid gases that reform) extracted as commercially valuable ‘recoveredresources’;

-   -   where Chlorine is removed as either hydrochloric acid (HCl), an        important industrial product, or as sodium chloride (NaCl),        commonly known as “salt” via reaction with sodium hydroxide        (NaOH),    -   where Elemental Mercury, Lead and other metals that may have        volatized and blown through with the process gas are extracted        in industrial grade forms;    -   where Sulfur that was not impounded within the melt or slag is        also extracted in a commercially valuable elemental or compound        form;

(s) the clean syngas can then be conditioned to meet the inputrequirements of any number of catalytic conversion processes to producea value-added product such as methanol; Fischer-Tropsch (F-T) Synfuel;

(t) the type and amount of feedstocks entered in the system are known(via electronic code, e.g., barcode, Quick Response Code, RFID, etc.);

(u) the entire system's operating parameters (minimum of 21 independentmonitoring and control systems) are controlled and managed by anintegrated Command/Control Management System;

(v) the energy in the system is monitored and adjusted (by controllingthe type, quantity, and quality of feedstocks) to maintain operatinglevels sufficient to generate required amounts of electricity (see (n)above);

(w) electricity is used to dissociate water liquid or steam to producecommodities of Hydrogen (H₂) and Oxygen (O₂).

Advantages of the inventive system include:

1. MMBG is separate and upstream of the A/C plasma reactor to:

-   -   a. Provide better thermal energy management;    -   b. Enable the system to use energy from the waste feedstocks to        sustain the melt, thereby reducing or eliminating the        requirement to sustain the melt from external energy sources;    -   c. Enable the system to scale the size of the MMBG and the A/C        plasma reactor independent of each other;    -   d. Use the melt as working media rather than as a heat sink to        impound a significant amount of the contaminates (inherent in        waste feedstocks) within the molten media, and preventing their        release and incorporation into the process gas stream, thereby        resulting in improved process and energy efficiency of        downstream gas clean-up processes;

2. Biogas from the anaerobic digester is used as a waste feedstockand/or a process gas for the A/C plasma reactor.

3. All wastes created by the system are reprocessed as a feedstock backinto the MMBG or A/C plasma reactor:

-   -   a. Solid phase material goes into the MMBG;    -   b. All other wastes go into either the MMBG or the A/C plasma        reactor.

4. Composition of feedstock is known prior to being input into thesystem.

5. Heat is recovered from all heat-generating elements and used tocreate steam and then electricity to reduce the operating cost of thesystem by generating its own electrical power.

6. The entire system is managed by an integrated Command/ControlManagement System to:

-   -   a. Allow control of the type and amount of feedstocks entering        the system;    -   b. Allow control of the system components to adjust operation        parameters to accommodate heterogeneity of waste material; and    -   c. Allow for off-site monitoring of the system.

7. The entire system is closed-loop, without producing combustion,greenhouse gas emissions, or landfill residuals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram illustrating the preferred embodiment of themechanical system for converting diverse waste materials into aconsistent quality syngas (that can be further processed into othercommodity products (e.g., methanol, synthetic fuels).

FIG. 2 is a flow diagram illustrating the preferred embodiment of thesystem for the recovery of heat and the conversion into steam to serveas a source of power to drive a generator to produce electricity.

FIG. 3 is a flow diagram illustrating the preferred embodiment of thesystem for end-to-end monitoring and controlling each of the componentprocesses, as well as the overall system.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Referring now to FIG. 1, the presently preferred embodiment of theinventive system 10 begins with the acceptance of heterogeneous wastematerials 100, 110, 120, which exclude, for example, Universal Wastes(see 40 CFR 273); explosives and munitions; radioactive materials;concentrated halogens and heavy metals. Waste products 100, 110, 120received are identified (via electronic code, e.g., barcode, QuickResponse Code, RFID, etc.) manually separated into three majorcategories for initial processing: 1) pumpable non-biodegradables 100;2) non-pumpable solid/semi-solid materials, and any other non-liquidwaste or secondary materials 110; and 3) biodegradables (e.g., plant,animal, and/or food industry waste) 120.

Biodegradable waste 120 is mechanically processed (shredding, grinding,milling, or other size reduction processes) by a biodegradables wasteprocessing utility 122 to which water or other liquids are added asneeded to produce a pumpable slurry 124 for input into a biogasgenerating system such as an Anaerobic Digester 140. In the preferredembodiment, one or more continuous multi-stage, thermophilic anaerobicdigesters are used. It is contemplated that one or more mesophilicanaerobic digesters may be used in combination with the thermophilicdigesters such as, for example, in a parallel arrangement.

Pumpable non-biodegradable waste 100 is strained and filtered 102through screens to meet the requirements of injectors used to inputliquids into the system. If the strained liquid material 104 containsmore than trace amounts of phosphorus, magnesium, or any otherpotentially highly reactive element, it must be input into the moltenmetal bath gasifier (MMBG) 130 for processing. Otherwise the liquidmaterial 104 may be input directly into either the MMBG 130 or the A/Cplasma reactor 150. Residual material larger than the required size forthe injectors 106 is recovered and input into the solids processingutility 112 for processing as a non-pumpable, non-biodegradable waste110.

Non-pumpable non-biodegradable waste 110 is processed by the Solid WasteProcessing Utility 112 to reduce the size of solid materials to a sizeranging from 0.5″ and 4.0″ (typical size range for commercialsize-reduction equipment) for efficient processing of the waste. Itshould be noted that larger sized waste material can be processed;however, processing efficiencies will be degraded (i.e., greater energywill be required for processing and the initial gasification process maynot be uniform). Processing includes cutting, grinding, shredding,milling or other size reduction processes. Decanting of containerizedwaste is not required, as the system will process both the waste and thecontainer. Following size reduction, the material 114 is input into theMMBG 130.

Input of waste material into the MMBG 130 serves as the first step inthe syngas production process. Several metals will suffice for themolten bath, but iron is used in the preferred embodiment due to itsabundant availability and its high melting point, thus allowing it toefficiently process a wide variety of diverse waste materials safely andefficiently.

Preferably, all materials are injected into the molten metal layerinstead of the atmosphere of the MMBG 130. An objective is to reduce theamount of time material is exposed to the atmosphere at the top of thecontainment vessel of the MMBG 130 in order to reduce the creation ofchar. In the preferred embodiment, input tubes, channels, and injectorsare angled downward and placed close to the level of the metal bath(above the slag layer). The material enters the MMBG 130 under pressurethrough the use of gravity, steam, pneumatic or mechanical force. Tubes,injectors, and/or channels placed inside the MMBG 130 are protectedusing refractory or other heat shielding material, or jacketing (heatexchanger) system.

While a variety of MMBGs can be used, a preferred embodiment uses a MMBGwith a molten iron bath operating within a temperature range of 1,150°C.-1,600° C. When materials are input into the melt, the syngasproduction process begins. The energy content of the inputs issufficient to maintain the molten state. Metals with a higher boilingpoint than the melting point of iron will smelt and become incorporatedinto the metal bath. The metal bath is periodically tapped and acommodity pig iron 136 is recovered. Minerals that melt, but do notvolatize, rise to the top of the molten bath and form a slag layer whichis periodically recovered as silicate glass 134. The gases formed, i.e.(process gas) 132, rise to the top of the reactor vessel and are inputinto the A/C plasma reactor 150 for further processing.

The MMBG 130 has multiple input ports and diverse materials aredissociated immediately upon exposure to the molten iron before they canreact (adversely) with other waste inputs, allowing a diversity of wastematerials to be processed. Furthermore, the molten metal bath is anefficient method for capturing the energy released from the dissociationof the materials and transferring that heat to the heat recovery steamgeneration system 200 as shown in FIG. 2. In addition, the MMBG 130 isan efficient apparatus for processing waste streams from other processesin the system (i.e., filtration systems 102; 142; 146), supporting theclosed-loop processing environment and eliminating the need foremissions.

The primary role of the anaerobic digester 140 is for the production ofbiogas. On average, the composition of the biogas from anaerobicdigester is about 75% CH₄; 18% CO₂; 1% N₂; 5% H₂O, and 1% O₂ and othertrace elements (H₂S and NH₃). The biogas from the Anaerobic Digester 145is processed and filtered by the Biogas Filtration 146 to remove acids,corrosives, or solid particulates which are typically produced in biogasproduction via anaerobic digestion, but which may degrade or impedeprocessing by the MMBG 130 and/or the A/C plasma reactor 150. Thefiltered biogas 147 is then input into the MMBG 130 and/or A/C plasmareactor 150. Waste generated from the Biogas Filtration 146 is inputinto the solids processing utility 112 for processing in the system. Theclean biogas 147 from Biogas Filtration 146 is used as an inputfeedstock for the MMBG 130 and the A/C plasma reactor 150. The biogasserves as an alternative to natural gas to increase the energy level ofthe system, generating heat which is recovered to create steam andgenerate electricity (see FIG. 2). It is also used as a working gas forthe A/C plasma reactor 150.

Wastewater (effluent) 141 is periodically recovered from the anaerobicdigester 140 and recycled 151 to add fluids to the anaerobic digesterand/or filtered by Effluent Filtration 142 for further processing. Thefiltered wastewater 144 is input into the MMBG 130, addingstoichiometric amounts of H₂ and O₂ into the system. The residualmaterial 143 from Effluent Filtration 142 is input into the Solid WasteProcessing Utility 112 for processing. Agricultural grade solids(digestate) 149 are periodically recovered as a commodity product.

The A/C plasma reactor 150 is used to complete the dissociation processof the gas derived from the MMBG 130. Instead of aiming the plasma plumedownward (as is the typical configuration in plasma gasifiers which usea plasma plume or plasma arc to dissociate solids and provide heat to anintegrated metal bath), the plasma plume in the A/C plasma reactor 150is advantageously aimed upward. Since no solid materials are injectedinto the plasma reactor (only gases and the occasional liquids), thereis no need for a molten bath to entrap residual elements at this pointin the process. All material input into the plasma reactor 150dissociate and reach a plasma state. As this material reaches the top ofthe reactor, it cools to a gaseous state, forming hot syngas 152, whichis input into a syngas cooling, cleanup, and conditioning system 160.Advantageously, configuring and using the plasma reactor 150 in thismanner requires less energy to operate than a conventionally configuredplasma gasifier that is used to dissociate solid materials and provideheat for a molten metal bath.

During the syngas cleanup and conditioning process in the Syngas Cleanupand Condition system 160, elements (e.g., Mercury, Lead, Chlorine,Sulfur) are filtered and removed to form a clean (contaminant free),high-quality syngas 166. The removed elements 162 are recovered ascommodity products using commercial equipment and processes. During thisphase, Oxygen (O₂) and Nitrogen (N₂) 164 are vented into the atmosphere,unless one or both elements are recovered as commodity products. Ifvented, these elements are commonly found in the atmosphere and areneither undesirable nor considered to be pollutants.

The clean syngas 166 is ready for further processing, which is achievedin the Product Recovery System 170 through catalytic conversionprocesses that are well understood by those knowledgeable in the art.The recovered products include methanol, and synthetic crude which canbe refined into a variety of synthetic fuels (e.g., diesel, and jetfuels).

In this inventive system, several processes are exothermic and heatgenerated by these processes is recovered to create steam to generateelectricity (FIG. 2). The generated electricity 282 is produced inamounts above and beyond the requirements needed to power all of thesystem processes (see energy balance equation below). The electricity282 is conditioned by a Power Conditioning System and Microgrid 290, anda portion of the conditioned electricity 292 is used to dissociate water(liquid or steam) in a utility 294 to produce commodities Hydrogen (H₂)296 and Oxygen (O₂) 298.

In the preferred embodiment, electricity is generated using a steamcycle only turbine instead of using steam and a portion of the syngas asa fuel in a combined cycle turbine. This allows the system to generateelectricity without requiring the use of combustion, thereby eliminatingthe need for smokestacks and the release of environmental pollutants.

In this system, there are five primary locations of heat generated byexothermic reactions. These include: the MMBG 130; the AnaerobicDigester 140; the A/C Plasma Reactor 150; the Syngas Cleanup andConditioning system 160; and the Product Recovery System 170 (dependingupon the catalytic conversion process employed). For each of theselocations or components 130, 140, 150, 160, 170, heat exchangers areinstalled to capture and transfer the generated heat from theselocations. Thus, heat exchangers 210, 220, 230, 240 and 250 are attachedor otherwise provided to 130, 140, 150, 160 and 170 respectively, asshown in FIG. 2. For each heat exchanger, a cool heat transfer medium(e.g., air; water; propylene glycol, etc.) 212, 222, 232, 242, and 252is pumped from the Heat Recovery Steam Generation (HRSG) Utility 270 toeach heat exchanger. The heat transfer media absorb heat from 130, 140,150, 160 and 170 via the respective heat exchangers 210, 220, 230, 240and 250 and are then cycled back to the HRSG 270 where the absorbed heatis used to convert water into pressurized steam. The pressurized steamgenerated 272 from the HRSG 270 is transferred to the Steam Turbine 280,which in turn generates electricity 282. The electricity is sent to aPower Conditioning System and Microgrid 290 where it is conditioned andredistributed 292 as conditioned electricity to power all of the systemprocesses. The Power Conditioning System 290 is used to assure qualityelectric power with a standard voltage in order to meet the operatingrequirements of the equipment in the inventive system and/or the localutility (if excess electrical power is returned to the local utilitypower grid). The Microgrid provides a means to manage and distribute thegenerated electricity for use by the inventive system and its processesor to be returned to the local utility power grid. In addition, theMicrogrid allows the inventive system to operate independently ofutility grid power. Excess electricity (i.e., above plant load) may beused to create H₂ 296 and O₂ 298 through electrolysis in the Hydrogenand Oxygen Utility 294.

Exhaust steam 274 from the Steam Turbine 280 is recycled to the HRSG 270for reheating. Similarly, excess steam/water vapor 262 is reheated byheat exchanger 260 and recycled 264 inside the HRSG 270. The regeneratedpressurized steam 272 is returned to the Steam Turbine 280 to generateelectricity.

In a preferred embodiment the heat recovery and steam generation processto generate electricity is net energy-positive (i.e., it produces moreelectricity than is required to power all of the processes throughoutthe system). Given the flexibility of the invention to adjust energyinputs (via the MMBG and the AD), there are many different ways this canbe achieved. Following is but one example of how this can be achieved:

-   -   a. Assume an input of non-biodegradable feedstocks with an        energy value of 8,600 BTU/lb at a rate of 25 TPH (tons per        hour).    -   b. Assume an input of biodegradable feedstock at a rate of 75        TPH.    -   c. Assume the following:        -   1. Gasification of one ton of non-biodegradables yields            30,000 scf of syngas.        -   2. One ton of biodegradable feedstock in an anaerobic            digester yields 4,842 scf of biogas.    -   d. Assume a high energy value of 340 BTU/scf of syngas.    -   e. Assume a high energy value of 750 BTU/scf of biogas.    -   f. Converting the unit of measure for the non-biodegradable        feedstocks from BTU/pound to BTU/ton yields 17,200,000 BTU/ton        (multiplying 8,600 BTU/lb×2000 [pounds/ton]). Therefore, at a        rate of 25 TPH, the non-biodegradable feedstocks contain an        energy value of 430,000,000 BTU/hour.    -   g. Multiplying the amount of biogas generated from the AD (4,842        scf/ton) times a rate of 75 tons per hour, yields 363,150 scf of        biogas per hour. Multiplying this amount by the energy value of        750 BTU/scf yields 272,362,500 BTU/hour.    -   h. Therefore, energy inputs from all sources into the system        yield 702,362,500 BTU/hour (BTU of non-biodegradables and the        anaerobic digester).    -   i. The amount of process gas produced from non-biodegradables is        750,000 scf/hour (30,000 scf/ton at a rate of 25 TPH) and the        amount of biogas produced by the anaerobic digester is 363,150        scf/hour (4,842 scf/ton at a rate of 75 TPH). Therefore,        1,113,150 scf of syngas is produced per hour by the system.    -   j. The energy value of the syngas is 378,471,000 BTU/hour        (multiplying 1,113,150 scf/hour×340 BTU/scf).    -   k. Assume a high value requirement of 4,400,000 BTU/ton of        non-biodegradable inputs to sustain the melt in the MMBG. Also        assume this energy requirement represents 80% of the total        energy used by all system processes. The energy needed to        sustain the melt is 110,000,000 BTU/hour (4,400,000 BTU/ton×25        TPH).    -   l. The energy used by all processes (excluding the MMBG) is        27,500,000 BTU/hour (derived from the assumption that the energy        needed to support the MMBG represents 80% of the total system        processes).    -   m. As shown in item h above, the system generates 702,362,500        BTU/hour. Of this amount, the syngas product consumes        378,471,000 BTU/hour, and the MMBG consumes 110,000,000        BTU/hour, for a total of 488,471,000 BTU/hour. This leaves        213,891,500 BTU/hour for all other resources. Since all system        processes excluding the MMBG require electricity, a conversion        from BTU to KWH is appropriate.    -   n. Assuming radiant and other heat loss of 20%, the amount of        energy lost equals 42,778,300 BTU/hour, leaving 171,113,200        BTU/hour available for heat recovery.    -   o. Assuming an 80% heat recovery efficiency, the amount of        energy available to convert into electricity is 136,890,560        BTU/hour (multiplying the residual energy of 171,113,200        BTU/hour×0.80).    -   p. Assuming a low value power efficiency of 25% for the steam        turbine, this yields 10,030 KW of electricity (Using a standard        BTU to KW conversion of the 136,890,560 BTU/hour in item o        above.).    -   q. The system resources, (excluding the MMBG), requires 8,060 KW        (using the standard formula of 3,412 BTU per KW).    -   r. This results in a net positive of electricity generated of        1,970 KW for use in the creation of H₂ and O₂, for resale to        local utilities, or other purposes.

Throughout this system, there are a minimum of 21 independent monitoringand control systems that collect data and manage local subsystemoperations and one input system for feedstocks. These independentmonitoring and control systems are comprised of myriad sensors thatmeasure temperature, pressure, moisture, chemical composition, flowrates, weight, etc. Some systems check for mechanical jams, contain firedetection equipment and may include cameras to allow visual inspectionof internal operations. Each of these monitoring and control systems isreadily available in the marketplace and is provided for each majorcomponent sub-system. However, each monitoring and control system isdesigned for specific sub-system operations and not for monitoring orcontrolling the entire system end-to-end. For example, the SolidsProcessing Utility 112 has an independent monitor and control system 304that measures and detects temperature, moisture, hose leaks, fires,equipment jams, etc., that are not shared with any other sub-processesin the system. Since downstream processes are dependent upon upstreamprocesses for effective operation, it is imperative that an integratedsystem collects data from each subsystem, monitors all of the operationsand allows for the management of the entire system and its componentsend-to-end. That integrated system is the Command/Control ManagementSystem (CCMS) 350 as shown in FIG. 3.

The CCMS 350 is an integrated system that collects data from all systemprocesses, integrating them into one overarching monitor and controlsystem, allowing end-to-end management of the entire process. The CCMS350 collects data from each subsystem and displays them on a dashboard,allowing an operator to view the status and operation of one or moresubsystems simultaneously. As shown in FIG. 3, these control andmonitoring subsystems include, for example: feedstock type, compositionand quantity 300; filtration of pumpable waste processes 302; solidnon-pumpable, non-biodegradable waste processing 304; biodegradablewaste processes 306; the anaerobic digester process (to include resourcerecovery) 308; effluent filtration processes 310; biogas filtrationprocessing 312; the MMBG process (to include resource recovery) 314; theA/C plasma reactor process 316; syngas cleanup and conditioningprocesses 318; product recovery processes 320; the hydrogen/oxygenutility process 322; the MMBG heat exchanger process 324; the anaerobicdigester heat exchanger process 326; the A/C plasma reactor heatexchanger process 328; the syngas cleanup and conditioning system heatexchanger process 330; the product recovery system heat exchangerprocess 332; the HRSG heat exchanger process 334; the HRSG processes336; the steam turbine process 338; and the power conditioningsystem/microgrid processes 340. The CCMS 350 also allows for centralizedremote access to any and all of these component subsystems to makeadjustments in system processes as needed. It can also shut the entirefacility down in the event of an emergency.

Thus, while fundamental novel features of the invention as applied to apreferred embodiment thereof have been described and pointed out, itwill be understood that various omissions and substitutions and changesin the form and details of the devices illustrated, and in theiroperation, may be made by those skilled in the art without departingfrom the spirit of the invention. For example, it is expressly intendedthat all combinations of those elements and/or method steps whichperform substantially the same function in substantially the same way toachieve the same results are within the scope of the invention.Moreover, it should be recognized that structures and/or elements and/ormethod steps shown and/or described in connection with any disclosedform or embodiment of the invention may be incorporated in any otherdisclosed or described or suggested form or embodiment as a generalmatter of design choice. It is the intention, therefore, to be limitedonly as indicated by the scope of the claims appended hereto.

What is claimed is:
 1. A system for efficiently converting heterogeneouswaste materials consisting of biodegradable and/or non-biodegradablewastes into a high quality syngas, comprising: (a) a first subsystem forreceiving and filtering pumpable, non-biodegradable waste; (b) a secondsubsystem for receiving and resizing non-pumpable, non-biodegradablewaste; (c) a third subsystem for receiving and resizing biodegradablewaste; (d) a molten metal bath gasifier (MMBG) having a molten metalbath for receiving the non-biodegradable wastes outputted from steps (a)and/or (b) into the molten metal bath, the MMBG outputting a process gasfrom the non-biodegradable waste; (e) an anaerobic digester, upstreamfrom the MMBG, for receiving the biodegradable waste outputted from thethird subsystem and for producing a biogas and effluent; and (f) analternating current (A/C) plasma reactor disposed downstream from theMMBG and the anaerobic digester, and receiving process gas from theMMBG, and biogas from the anaerobic digester as a process gas and/or aworking gas; with the A/C plasma reactor converting the process gasesfrom the MMBG and the anaerobic digester into a plasma phase andoutputting raw syngas.
 2. The system of claim 1, wherein the anaerobicdigester is thermophilic operating at a temperature between about 49° C.and 57° C.
 3. The system of claim 1, wherein the anaerobic digester ismesophilic operating at a temperature between about 20° C. and 40° C. 4.The system of claim 1, wherein the A/C plasma reactor contains a plasmatorch that is positioned to allow the plasma plume to be orientedupward.
 5. The system of claim 1, wherein the non-biodegradable wastesexclude Universal Wastes defined in 40 CFR 273, explosives andmunitions, radioactive materials, concentrated halogens and heavymetals.
 6. The system of claim 1, further comprising a fourth subsystemfor filtering and conditioning the outputted syngas from the A/C Plasmareactor.
 7. The system of claim 6, further comprising a product recoverysystem for converting the conditioned syngas from the fourth subsysteminto methanol and/or synthetic fuels.
 8. The system of claim 2, whereinthe biogas from the thermophilic anaerobic digester has an averagecomposition 75% methane, 18% carbon dioxide, 1% nitrogen, 5% watervapor, 1% oxygen, and trace elements including hydrogen sulfide andammonia.
 9. The system of claim 3, wherein the biogas from themesophilic anaerobic digester has an average composition of 65% methane,28% carbon dioxide, 1% nitrogen, 5% water vapor, 1% oxygen, and traceelements including hydrogen sulfide and ammonia.
 10. The system of claim1, wherein the MMBG is configured to receive the biogas from theanaerobic digester.
 11. The system of claim 1, wherein the firstsubsystem produces a liquid from the filtered pumpable,non-biodegradable waste, and the A/C plasma reactor is configured toreceive the liquid from the first subsystem.
 12. The system of claim 1,wherein the molten metal bath comprises iron.
 13. The system of claim 1,wherein the filter waste is inputted into the MMBG and/or the A/C plasmareactor.
 14. The system of claim 1, wherein the system for theconversion of heterogeneous waste materials into high quality syngasdoes not emit any greenhouse gases or residual landfill materials. 15.The system of claim 1, further comprising a biogas filtration subsystemfor filtering the biogas from the anaerobic digester for use as aworking gas and/or process gas for the MMBG and/or A/C plasma reactor,and an effluent filtration subsystem for filtering the effluent for useas a feedstock to the MMBG.